Unless something drastic and different is done, the world’s atmosphere will go on being destroyed by the production of Portland cement, which is a far worse source of atmospheric pollution than the oil industry or any other known industry. The fact that the dangers to the world’s ecological system from the manufacture of Portland cement is so little known by politicians and public makes the problem all the more urgent: when nothing is known, nothing is done.
This situation clearly cannot continue if the world is going to survive. The conversion of existing cement factories to clean production of geopolymeric cement does not necessitate any re-equipment. The same grinders and the same ovens can be retained for the new process, but the ovens are merely run at half-temperature. For geopolymeric cement production, no temperature higher than 750°C is ever needed. This means that only one third of the fuel requirement is needed for cement production, and of course the fuel emissions are thus reduced by two thirds. This means local benefits for coal-burning regions, with drastic reductions in sulfur dioxide and nitrogen emissions, as well as suppression of particulate emissions. But the main benefits of geopolymeric cements are the reductions in carbon dioxide: the chemical process emits zero carbon dioxide, and the fuel much less, so the end result is a reduction in carbon dioxide emissions for cement manufacture of between 80% and 90%.
There is no other existing and proven technology in the world today which offers such hope for saving the world’s atmosphere.
In the recently updated book Geopolymer Chemistry & Applications Low-CO2 geopolymer cement applications are thoroughly outlined in Chapters 9, 10, 11, 12 and 24.
From the scientific press: NEW SCIENTIST, 19 July 1997, page 14
THE CONCRETE JUNGLE OVERHEATS:
Estimates of carbon dioxide emissions from one of the world’s growth industries
have been grossly underestimated.
“CEMENT kilns contribute more to the world’s output of carbon dioxide than aircraft and could soon be responsible for 10 % of all emissions of the greenhouse gas. New calculations by an industry scientist reveal that cement manufacturers already produce 7 % of global CO2 emissions-almost three times previously published estimates, and that CO2 output is increasing faster from cement works than from any other industrial source.
Cement production creates CO2 in two ways: by the conversion of calcium carbonate to calcium oxide inside the kilns, and by burning large quantities of fossil fuels to heat the kilns to the 1450°C necessary for roasting limestone. Previous estimates for CO2 emissions from cement production have concentrated only on the former source. The UN’s Intergovernmental Panel on Climate Change puts the industry’s total contribution to CO2 emissions at 2.4 %; the Carbon Dioxide Information Analysis Center at the Oak Ridge National Laboratory in Tennessee quotes 2.6 %.
Now Joseph Davidovits of the Geopolymer Institute, a research institution based in Saint-Quentin, Picardie, France, has for the first time looked at both sources. He as calculated that world cement production of 1.4 billion tonnes a year produces 7 % of current CO2 emissions. This puts it behind power generation and vehicle exhausts as a source of the gas, but ahead of aircraft, which have excited huge attention from politicians concerned about curbing global warming.
Dale Kaiser at Oak Ridge confirmed this week that “our calculation only singles out the chemical transformation aspect”. (…) John Lanchbery director of environmental projects at the Verification Technology Information Centre in London, who analyses national CO2 emissions inventories, says: “Cement is well known as the biggest manufacturing source of CO2, but I certainly had no idea the total was as high as is being suggested.”
Globally cement production is rising by 5 % a year, says Davidovits. He predicts that it will be responsible for a tenth of global CO2 emissions by 2000. It is growing fastest in the “tiger” economies of east Asia, where construction of buildings, roads and other infrastructure is booming. In Korea, the industry is already responsible for an estimated 13 % of the country’s CO2 emissions. (…) The silence on cement manufacture as a cause of global warming contrasts with the growing concern over aircraft emissions, which are estimated to contribute a maximum of 5 %. Last month at the Earth Summit in New York, the European Union called for a global tax on aircraft fuel. But proposals for an internal EU tax on energy aimed at reducing CO2 emissions, specifically excluded the cement industry because its energy use is so high that it was thought a tax would damage it. Fred Pearce